Desulfurization of heavy petroleum oils



y 1953 R. B. MASON ET AL DESULFURIZATION 0F HEAVY PETROLEUM OILS Filed Nov. 17, 1950 r m oum -01 Al ms am Poo/ 1 10.. I Q

muu m I 795004 Dmmu Immuu IV dmJtmm am w 20 59 51 Unvenbors 2:3 Qt'corng Patented May 26, 1953 DESULFURIZATION OF HEAVY PETROLEUM OILS Ralph Burgess Mason and Harold J. Rose, Baton Rouge, La., assignors to Standard Oil Development Company, a corporation of Delaware Application November 17, 1950, Serial N 0. 196,156

9 Claims.

The present invention relates to the treatment of sulfur-containing organic materials, in particular, sulfur-bearing hydrocarbon material, to desulfurize the same. More particularly, the present invention relates to the desulfurization of sulfur-containing petroleum fractions, particularly heavy fractions, such as residua and reduced crudes.

The problem of sulfur removal from petroleum fractions and crudes is as old as the petroleum industry. For most purposes, it is undesirable to have an appreciable amount of sulfur in any petroleum products. Gasoline should be relatively sulfur-free to make it compatible with lead. Motor fuels containing sulfur as mercaptans are undesirable because of odor and gum formation characteristics. Sulfur is objectionable in fuel oils of any kind because it burns to form S02 which is obnoxious and corrosive.

Sulfur occurs in petroleum stocks, generally in two main forms, as mercaptans and as part of a more or less substituted ring, of which thiophene is the prototype. The former type is generally found in the lower boiling fractions, in the naphtha, kerosene, and light gas oil material, whereas the ring-sulfur compounds form the bulk of the sulfur-bearing material of the high boiling petroleum fractions. Numerous processes for sulfur removal from relatively low molecular and lower boiling fractions have been suggested such as doctor sweetening, wherein mercaptans are converted to disulfides, caustic treating, solvent extraction, co p r chloride treating, etc., all of which give a more or less satisfactory decrease in sulfur or inactivation of mercaptans by their conversion into disulfides. The latter remain in the treated product, and must be removed if it is desired to obtain a sulfur-free product.

Sulfur removal from higher boiling fractions, however, has been a much more dimcult operation. As pointed out, here the sulfur is present for the most part as a part of a ring. Such sulfur is, of course, not susceptible to chemical operations satisfactory with mercaptan sulfur. Also, extraction processes are unsatisfactory, for solvents specific for sulfur compounds, for instance, lboron fluoride complexes or liquid hydrogen fluoride-boron fluoride, or liquid S02, no longer are of much use when possibly every molecule of the oil contains a sulfur ring. Thus, a high boiling product, such as a residuum that contains about 3% of sulfur is estimated to consist extensively of molecules containing sulfur, and so extraction of sulfur-containing material 2 is no longer feasible, inasmuch as the bulk of the extracted material is in the extract and lost, unless a means is present for removing sulfur from this extract.

One satisfactory method for removing sulfur from products wherein it is present as a ring type compound has been by hydrogenation in the presence of a so-called sulfactive catalyst. Thus, it has been found that certain catalyst, such as cobalt molybdate, tungsten sulfide, nickel sulfide, molybdenum sulfide, etc., are good hydrogenation catalysts and that when these catalyst substances are employed in the hydrogenation of petroleum stocks containing sulfur, these catalysts are not poisoned by sulfur but, on the contrary, tend to reduce the sulfur content of the material being hydrogenated, the sulfur being removed as H23. However, though this process is quite satisfactory for the hydrogenation, or hydrodesulfurization of low and medium boiling petroleum fractions, the process is completely unsatisfactory for sulfur removal from high boiling stocks, such as cycle stock and residua. The latter, which are the bottoms product after the 1050 F. gas oil is taken overhead, are notorious carbonizers. When they are passed over a fixed bed of a sulfactive catalyst of the type described above, in order to remove a portion of the sulfur content by catalytic hydrodesulfurization, carbonization of the catalyst proceeds at once, and in an extremely short time the catalyst is covered by deposition of carbonaceous material and is inactivated. Regeneration is expensive, and since the period of activity is so short, it is economically unfeasible to operate with such a process.

It is, therefore, an object of the present invention to provide an improved method of desulfurizing sulfur-bearing organic hydrocarbon material, in particular, desulfurizing high boiling stocks such as residua.

A further object of the invention is to provide an improved means of refining petroleum fractions to separate therefrom sulfur and undesirable sulfur compounds.

A still further object of the present invention is to provide a cheap method for upgrading heavy stocks such as residua.

A still further object of the present invention is to disclose a novel means of hydrodesulfurizing in the absence of a fixed catalyst bed whereby inactivation of catalyst is substantially avoided.

Other objects and advantages of the present invention will become apparent from the follow- 3 4 i s description, r d in conjunction with the acably, though not of necessity, in the further prescompa y ng drawing escribing O e embodimen ence of a hydrogen halide promoter such as HCl. of the present invention. Because the liquid catalyst is dissolved in and It has now been found that these objects and dispersed through the sulfur-containing feed, the advantages may be realized by subjecting sulfur- 5 deposition of carbonaceous solids, as asphaltenes, containing high boiling hydrocarbon material, and of ash, does not inactivate the catalyst as a such as reduced crude and residua, to a hydrofixed catalyst bed of sulfactive catalyst would desulfurization reaction employing, instead of a have been inactivated.

fixed catalyst bed, a homogeneous catalyst which The invention will best be understood when is not fouled and inactivated by the large quark 19 read in conjunction with the accompanying drawtities of asphaltenes and ash present in such soing which is a diagrammatic representation of a called dirty feed stocks, thereby making it pospreferred embodiment of the invention.

sible to dispense with the expensive and easily- Turning now to the figure, wherein there is fouled heterogeneous catalysts, such as molybdeshown diagrammatically, a procedure for hydronum sulfide, tungsten sulfide, etc. desulfurizing and upgrading a heavy residuum,

By a homogeneous catalyst system 15 @Qfil'tii such as Kuwait bottoms in the presence of the y m wherein the catalyst is, l ys pr en liquid catalyst of the present invention, the pea fresh surface to the e c a a System troleum stock is introduced through lines 2 and 6 having a self-generating Su Such a, system into reactor I 9, together with catalyst either from is fully realized When h catalyst s completely 20 storage through lines 4 and 6, or in part from remisoible in the material bei g t a d, and cycled or regenerated catalyst, as shown herein- 5 extent h n ata t i comp et y after. The liquid mixture is contacted counter- D l h ue nd. th f i i l p duc currently with a hydrogen-containing gas introcomplise a Separate p s ti n, l f ii pr duced through line l2. Hydrogenator I0, is suitcipitating, fresh sur c 15 WWWQU provided ably a packed tower, though other known means It a now be f n hat the hig e Valent of obtaining intimate contact between liquids halides of the amphoterio metals, in particular, and gases may be employed, Stannifi chloriiie a ti an um tetrachloride, are Within vessel It] there is maintained a pressure partic r y useful as homo ne catalysts in of from about 100 to 5000 p. s. i. '9, preferably reduci t sulfur ont nt of du d crudesend 1 500 to 3000 p. s. i. g., depending upon the nature residue, in the pr s nc O yd e Resldua of the material being treated, and temperatures e little commercial lue because of their in the range of 3.00" to 900 F., preferably between high coking ch acteristics andsulfur content, F. are employed Feed mtes of 01.25 to besides containing large amounts of ash and as- 4 may be used together with hydrogfm phaltenes. In accordance with the present 111- feed rates of about 500 to 5000 standard Cubic vention, res dua and reduced crudes may be 1eadfeet per barrel of liquid feed Though comma? 3 and economically nv ed nt? usfullprod' cial hydrogen is to be preferred, even hydrogen ucts, such as feed stock for catalytic cracking, or containing appreciable ts of CO a e for bunker and marine fuel, none of which prodused ucts can tolerate high sulfur content. Th 1 e amount of catalyst employed in the hydro It s known inflthce 1atrt tfohtreat suliui cfiontail g na i may y r m 2 to 20% by Weight! on s 0 Stocks i 5 Q V me a S 0 the feed, depending in part upon the amount of merize olefinic material and to precipitate asphaltenes' This treatment howqver re- In accordance w th the re'ent inventio h move Sulfur whet-1: the Sulfur is firmly attached drogen chloride is introa uc ecl into react or to the ring of the on molecuie and? i through line 8. This material is most ef ective containing molecules compri e substantially the in prbmotihg the ydrodemfurizatibh i -action Whole of the oil being treated, as where a reduced within m may be added ominuofisly 6r m Crude t example contams 3 9 P termittently to the extent on to 15% by weight fur; this corresponds to a mixture wherein the of hydrocarbon fed I vast bulk of the molecules contain sulfur and are, Product streams Containing in p on con- $1 35 e ti tifi iii titefitfi ee excellent hosiderbleamounts vciairbbnaceouvsi solids, s mogeneous catalysts for the hydrodesulfurization g if g i 3323155 22523: g ggz tz l lgii of these heavy stocks, because such halides are to a considerable extent, soluble in the hydrocarbon ghrouglflthe qw i gie o r a Wi as a result of the hydrogenation, thesolid' sulfides. vmwn from mac or mug lmes 2n andpassedl are formed which do not inactivate. the. catalyst Settling Vessels Sludge and, solids as they would. tend to.v if the, latter w re a. solid, r o e 9 S ttle- Llquld P c s ar raw by forming a coat of the respective sulfideabout off through 111168 25 and a may, if 1.85 3 the catalyst. The catalyst i readily regenere 6Q b Pa to 93 3 1 e i 11119 In 9 1 1 9 atable from the reaction products and. may be hen duqtmay b e fl l With an alkaline material, asclilutecaustic, et o. to remove residual It has further been found thatthe actiyity of: HClf desired, how l q i p oduct. may th se h mogeneous nyclrodesuliurization atalysts. y-n st Scrubber 5. nf-P 11118 40, an pass may be substantially enhanced and; promoted by; Q5 directly to fractionatpr 4]. Overhead there; is

promoter, if any, added to the reaction system.

carry t e hydrqd suliur zation theme ec edt ue line 42 a u ahy ulfurerice dfa hy -h ide sashes ee naph ha il through 111 4. and 4 o In accordance with the presentinvention, high, sulfu as and heating oils. may be withdrawn.

. la n,- t a Res du is i h ra hrough. line 48, and this tions, particularly reduced crudes and residue, may be recovered as such, as when it is, desired are treated in a hydrogenation z onewith hydro; to recover bunker fuel, or it may be recycled in gen at pressures, from, about too-599g a, s: smast as a o e ot nro s ia n and at temperatures in the range of 3009 QQ," Returning to hydrogenator I0, gaseous prod,- referab y b tween, 4, an 809 E111}- e ii si usts comprises. unne ded d gen, CL, Hrs,

bai in i h mo cula we ht. net

ii e ft n 1f e iiilmjte rtshiensia anaemiais, nd; some hydrocarb i uids a d cases,- results? Furthermore, though the present invention finds its greatest utility in upgrading reduced ,crudes and residua, the invention may also be employed in the upgrading and desulfurizing of other material, such as shale oil, petrolatum, etc., in particular, those boiling above about 650 F.

The effectiveness of the halides of tin and titanium as homogeneous catalytic agents in the hydrodesulfurizing of heavy feed stocks is clearly demonstrated in the following example. The material desulfurized was a 78% Kuwait bottoms fraction.

Hydrodesulfurizing of 78% Kuwait bottoms Run Feed A B C D E F Catalyst None $11014 $21014 T1014 SnClz SnOln Wt. Percent Catalyst 5 5 5 Wt. Percent H01 promoter 6 6 0 6 Added Gas... H2 H2 H2 H2 H2 H1 Pressure, p. s. 1. g- 2, 000 2,000 2, 000 2,000 2, 000 2,000 Temperature 750 750 750 0 75 750 Sulfur, Wt. Eercent- 3.07 2. 23 1. 36 1.0 O 79 1.59 1. 36 Dcsulfurizatlon, Wt. Percent 27. 3 56 67. 5 74 48. 2 55. 7 Product Distribution:

Naphtha, 400 F.-

Wt. Percent of product 0 20. 5 3. 2 3. 5 6. 2 l. 5 1. 7 Gravity, API 72. 4 69.8 69. 8 72. 1 69. 2 0. 07 0. 06 0. 21 0. 0. 07 Gas Oil, 850 F.-

Wt. Percent of product 50. 2 60. 8 76. 9 S1. 3 84. 7 75.0 77.4 Gravity, API 32.1 33.5 32. 7 84.8 32. 9 33.1 Sulfur, Wt. Percent. 1. 70 2.08 1. 0.83 0.72 1. 33 1. 21 Gas Oil Bottoms Wt. Percent of product 49.8 18. 7 l9. 9 15. 2 9. 1 23. 5 20. 9 Sulfur, Wt. Percent 4. 41 5. 04 2. 22 2.14 l. 8 2. 49 2.07

reactor l0, with or without prior removal of HzS by any conventional method.

The settled solids in settlers 22, which consist in large proportions of tin or titanium sulfide, as well as Sn or Ti compounds dispersed or occluded in the carbonaceous solids and ash, are advantageously treated with a halogen, preferably chlorine, to recover the catalyst. This may advantageously be accomplished by injecting C12 through lines 54 into settlers 22. As a result of the ensuing reaction, preferably aided by a suitable heating process, the sulfides, etc. are reconverted into the respective high valent halides. The regenerated catalyst and unreacted chlorine may be withdrawn overhead from 22 via line 56 and, after cooling, allowed to separate into a liquid and gas phase respectively in separators 58. The chlorine may be recycled for further conversion in settlers 22, while the liquid SnCl4 or TiCh may be passed downwardly through line 62, and thence through lines 64 and 6, back to the reaction system.

The above description and exemplary operation admit of many variations obvious to those skilled in the art. Thus, mention has not been made of various accessory equipment which normally would be used in a commercial plant. Thus, in the interest of good heat economy, various heat exchangers and economizers would be employed to utilize whatever heat is available in the most efficient manner and, in order to control the process, pumps, compressors, agitators, valves, flow meters, etc., would be included in the equipment. Also, it may be desirable to withdraw coke and precipitated sulfides from settlers 22 and to treat the solids for catalyst recovery in suitable auxiliary equipment. Under certain circumstances it may be desirable to pretreat the residua or reduced crude with hydrogen in the absence of a catalyst or promoter prior to homogeneously catalytically hydrodesulfurizing the same; appreciable reduction in amount of catalyst required may sometimes thus be realized.

The above data clearly show the effective desulfurization to be obtained by the use of stannic or titanium tetrachloride in accordance with the hydrodesulfurization process of the present invention. It will be noted that the beneficial effects of the metal halides, are considerably enhanced by the addition of the hydrogen halide promoter. Even stannous chloride which, being a solid, and thus not a homogeneous catalyst and which did not show particularly high desulfurization characteristics, had its efficiency enhanced by the presence of added 1101 promoter.

It is also of interest to note that the bottoms product, as a result of the treatment in accordance with the present invention, has been upgraded into a form readily utilizable as feed to the catalytic cracking process, and that the halides themselves, particularly when promoted with H01, show good cracking characteristics, as shown by the increased yields of the distillate fractions when HCl is employed. Furthermore, it will also be noted that desulfurization in the lower boiling fractions resulting from the treatment is practically complete.

While the foregoing description and exemplary operations have served to illustrate specific applications and results of the invention, it is not limited thereto. Other modifications obvious to those skilled in the art are within its scope.

What is claimed is:

1. The process of desulfurizing and upgrading sulfur-containing petroleum residua which comprises contacting said residua feed in a hydrogenation zone with hydrogen in the presence of a catalyst comprising the tetrachloride of a metal selected from the group consisting of tin and titanium, maintaining within said zone, a pressure in the range of to 5000 p. s. i. g. and a temperature in the range of 300-900 F., and recovering a hydrocarbon product containing substantially less sulfur than said feed.

2. The process of claim 1 wherein a hydrogen halide promoter is added to said hydrogenation 7 3. The process of claim 2 wherein said promoter is HCl.

4. The process of claim 1 wherein said catalyst is SnCh.

5. The process of claim 1 wherein said catalystis TiC14.

6. The process of claim 1 wherein said catalyst and said feed form substantially a single phase.

7. The process of claim 1 wherein 2 to 20% by weight of catalyst is added to said zone.

8. The process of claim 1 wherein said feed is contacted with hydrogen and partially desulfur ized before addition of catalyst to said zone.

9. The process of desulfurizing and upgrading sulfur-containing petroleum residua which comprises contacting said residua feed in a hydrogenation zone with hydrogen in the presence of a catalyst comprising the tetrachloride of a metal selected from the group consisting of tin and titanium, maintaining within said zone a pressure in the range of 100-5000 p. s. i. g. and a temperstate in the range of 300-900' R, adding 1 to about 15% of HCl promoter based on petroIeum feed to, said zone, and recovering a hydrocarbon product containing substantially lessv sulfur than said feed.

RALPH BURGESS MASON.

HAROLD J. ROSE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,814,410 Richter et a1 July 14, 1931 FOREIGN PATENTS Number Country Date 3,313 Great Britain 1873 421,858 Germany Nov. 19, 1925 OTHER REFERENCES Torossian, Ind. and Eng. Chem., vol. 13, p. 903, Oct. 1921., 

1. THE PROCESS OF DESULFURIZING AND UPGRADING SULFUR-CONTAINING PETROLEUM RESIDUA WHICH COMPRISES CONTACTING SAID RESIDUA FEED IN A HYDROGENATION ZONE WITH HYDROGEN IN THE PRESENCE OF A CATALYST COMPRISING THE TETRACHLORIDE OF A METAL SELECTED FROM THE GROUP CONSISTING OF TIN AND TITANIUM, MAINTAINING WITHIN SAID ZONE, A PRESSURE IN THE RANGE OF 100 TO 5000 P.S.I.G. AND A TEMPERATURE IN THE RANGE OF 300*-900* F., AND RECOVERING A HYDROCARBON PRODUCT CONTAINING SUBSTANTIALLY LESS SULFUR THAN SAID FEED. 